Currently, devices wearable by the user's body while performing as various smart functions have been developed. Representative examples of the wearable devices may include a smart watch, a smart glass, and the like. The smart watch is wearable on the wrist like a traditional analog or digital watch and provides various functions for making a call like a cellular phone, sending text messages or email, web surfing, and the like. The smart glass provides various smart functions such as photographing an object or viewing an image while being worn on the user's body like traditional eyeglasses.
In this case, the wearable device is worn on a part of the user's body and thus partially contacts the user's body. A general device needs to generate a sound or display specific information on a display in order to indicate an operation state. However, the wearable device has the feature whereby the device contacts the user's body and thus has another method for indicating an operation state to a user. That is, a stimulus is given to a user's body to indicate an operation state of the device to the user. The method for giving a stimulus to the user's body to indicate an operation state of the device to the user may be very useful because a simple operation of the device to a complex state of the device is indicated to the user. Thus, a method for giving a stimulus to a user is important. In this case, there is a need for an appropriate method for designing a wearable device.
The above information is presented as background information only to assist with an understanding of the present disclosure. No determination has been made, and no assertion is made, as to whether any of the above might be applicable as prior art with regard to the present disclosure.